#login{
    /*背景图片加载*/
    background-image:url("../img/login_bg.png");
    background-repeat: no-repeat;
    background-size:1500px 800px;
}
/*标题加载*/
#logo{
    font-family: 微软雅黑;
    font-size:60px;
    position:absolute;
    top: 50px;
    margin-left: 50px;
    color: white;
}
#app{
    margin-top: 300px;
    margin-left: 500px;
    width: 500px;
}
/*用户名和密码的输入框*/
#username{
    background: Transparent;
    color: white;
    height: 50px;
    width: 500px;
    border: 2px solid white;
}
#password{
    background: Transparent;
    color: white;
    height: 50px;
    width: 500px;
    border: 2px solid white;
}
/*登陆按钮*/
#denglu{
    border: 2px solid white;
    background: burlywood;
    color: white;
    margin-left: 150px;
    width: 200px;
    height: 50px;
    font-size: x-large;
}
/*提示信息*/
.tip{
    color:red;
}